Road structure – process – or apparatus – Process – In situ treatment of earth or roadway
Reexamination Certificate
2002-06-14
2004-08-03
Hartmann, Gary S. (Department: 3671)
Road structure, process, or apparatus
Process
In situ treatment of earth or roadway
C404S091000
Reexamination Certificate
active
06769836
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a process and machinery (Preheaters and Recycling Machine) for accurately heating, milling/profiling, handling and placement to grade of 100% Hot In-place Recycled (HIR) asphalt mixed with various types of rejuvenating fluids, liquid polymers and aggregates, with or without the addition of new, virgin asphalt (produced by a standard asphalt plant). The asphalt pavement is heated and softened by two or more Preheaters, physically scarified by one or more sets of carbide cutters (rakes), profiled and collected by mills, measured and mixed with rejuvenating fluid, polymer liquid (if required) and washed aggregate (if required) in a pug mill. The type, and amount of additives required to 100% HIR asphalt pavement is specified by pre-engineering using core samples taken from the asphalt pavement at regular intervals.
The 100% HIR of asphalt pavement is achieved by the addition of rejuvenator fluid, liquid polymers (if required) and washed aggregate (if required). Rejuvenator fluid must be accurately metered, as too much rejuvenator fluid will cause the recycled asphalt to bleed (rejuvenator fluid rising to the surface) softening the compacted surface. Too little fluid will not restore flexibility back into the recycled asphalt.
Liquid polymers such as Latex are added to increase the performance of the 100% recycled asphalt (Superpave specifications) by increasing flexibility while reducing rutting and cracking over a wider operating temperature range.
Adding aggregate (typically washed sand) during the 100% HIR process will modify the asphalt's physical properties and the air void ratio (percentage of air entrenched in the asphalt and generally specified at between 3-5%).
Adding rejuvenating fluid alone to the recycled asphalt will generally reduce the air-void ratio while adding washed sand tends to increase the air-void ratio. Adding aggregates that contain dust (unwashed) will generally reduce the air void ratio. Pre-engineering determines the correct specification and application rates for rejuvenating fluid, polymer liquid and aggregate. The Recycling Machine is designed with modular pin-on attachments for increased flexibility.
SUMMARY OF THE INVENTION
The present invention has a wide range of processing capabilities. For example, it can be used in, among others, the following applications:
1. 100% HIR: The old asphalt pavement is heated by a plurality of Preheaters to soften the asphalt for processing by the Recycling Machine. The final Preheater may be fitted with carbide cutters, asphalt collection blades (rake assembly) and an aggregate distribution system. The old asphalt is physically scarified by carbide cutters (rakes), profiled and collected by mills, measured and mixed with rejuvenating fluid, polymer liquid (if required) and washed aggregate (if required) in a pug mill. In one embodiment of the present invention, as described below, the asphalt from the heated surface does not need to be lifted. The type and amount of additives required to 100% HIR asphalt pavement is specified by pre-engineering using core samples taken from the asphalt pavement at regular intervals.
The 100% HIR of asphalt pavement is achieved by the addition of rejuvenator fluid, liquid polymers (if required) and washed aggregate (if required). Liquid polymers such as Latex are added to increase the performance of the 100% recycled asphalt (Superpave specifications) by increasing flexibility while reducing rutting and cracking over a wider operating temperature range.
Adding aggregate (typically washed sand) during the 100% HIR process will modify the asphalt's physical properties and the air void ratio (percentage of air entrenched in the asphalt and is generally specified at between 3-5%). The 100% recycled asphalt is placed to grade as a single course (layer) by a standard paving screed (attached to the Recycling Machine).
The Recycling Machine can be equipped with an optional front asphalt hopper/variable speed chain slat conveyor, truck pusher bar, variable speed central belt conveyor and electronic belt scale and conveyor hopper/diverter valve. A surge bin/vertical elevator, auger/divider/strike off blade, and screed assembly are also provided. The Recycling Machine's mills, pug mill, auger/divider/strike off blade and screed assembly, process and place the 100%, recycled asphalt. When equipped with the optional equipment, the Recycling Machine's on-board computer meters the new asphalt, which may be stored in a hopper, into the surge bin/vertical elevator, auger/divider/strike off blade and screed assembly for startup. The optional equipment also allows the Recycling Machine to perform the 100% HIR Remix method.
2. 100% HIR (Remix): In this application, the old asphalt pavement is heated by three or more Preheaters to soften the asphalt for processing by the Recycling Machine. The final Preheater may be fitted with carbide cutters, asphalt collection blades (rake assembly) and an aggregate distribution system. The Recycling Machine can be equipped with a front asphalt hopper/variable speed chain slat conveyor, truck pusher bar, variable speed central belt conveyor and electronic belt scale, conveyor hopper/diverter valve, surge bin/vertical elevator, auger/divider/strike off blade, and screed assembly. New asphalt is delivered from the hot mix plant by highway dump trucks and discharged into the Recycling Machine's hopper. The Recycling Machine's on-board computer meters the new asphalt (stored in the hopper) proportionally (approximately 10% to 15% by weight of the asphalt being 100% recycled) on to the central belt conveyor. A hopper/diverter valve diverts the new asphalt into the surge bin's vertical elevator. The vertical elevator is positioned in the 100% processed asphalt's windrow to continuously pickup asphalt. The processed asphalt and the metered, new asphalt are blended at the vertical elevator and delivered to the surge bin. The new asphalt may also be diverted directly on to the 100% recycled asphalt (windrow) exiting the pug mill.
3. 100% HIR (Integral Overlay): In this application, the old asphalt pavement is heated by a plurality of Preheaters to soften the asphalt for processing by the Recycling Machine. The final Preheater may be fitted with carbide cutters, asphalt collection blades (rake assembly) and an aggregate distribution system. The Recycling Machine is equipped with a front asphalt hopper/variable speed chain slat conveyor, truck pusher bar, variable speed central conveyor, shuttle conveyor, primary asphalt distribution auger/divider/strike off blade, secondary asphalt distribution auger and primary/secondary screed assemblies. New asphalt is delivered from the hot mix plant by highway dump trucks and discharged into the Recycling Machine's front hopper. The Recycling Machine's mills, pug mill, primary auger/divider/strike off blade and screed assembly, process and place the 100% recycled asphalt. The Recycling Machine's on-board computer meters the new asphalt (stored in a hopper) via the central conveyor and shuttle conveyor to the secondary asphalt auger and screed assembly and if required, to the primary auger/divider/strike off blade and primary screed assembly. The new asphalt is placed by the secondary screed assembly on top of the 100% recycled asphalt (being laid to grade by the primary screed assembly) resulting in a hot, thermal bonding between the two layers. The 100% recycled and new asphalt is not mixed together, as in the Remix method. Both the primary and the secondary screed assemblies feature a novel grade control system used to place the asphalt to grade while also controlling the depth differential (generally 0.5 to 1 inch) of the asphalt laid between the two screed assemblies.
A standard, asphalt-paving machine used in the industry is designed to lay hot, plant mix asphalt delivered from the asphalt plant by dump trucks. The paving machines are either rubber tire or track driven machines. Neither type has any hydraulic suspension to r
Enviro-Pave, Inc.
Hartmann Gary S.
Michael P. Mazza, LLC
LandOfFree
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